Multifunctional (meth)acrylate polysaccharide microcapsules

Abstract

The invention describes a core shell microcapsule wherein the capsule shell is an interfacial copolymer formed of a modified polysaccharide free radical cross-linked with a multifunctional (meth)acrylate. The polysaccharide is hydrophobically modified with an adduct containing at least one unsaturated bond. The modification imparts hydrophobic character to the polysaccharide to act as an emulsifier, driving the modified polysaccharide to an oil-water interface of an encapsulation emulsion described, and creates an active bonding site for free-radical polymerization between the polysaccharide and multifunctional (meth)acrylate, thereby forming a microcapsule shell surrounding the core material.

What we claim is: 
     
         1 . A microcapsule comprising a core material and a shell encapsulating the core material,
 wherein the shell comprises i) a multifunctional (meth)acrylate having a vinyl group cross-linked with a hydroxyl group, carbon, or (meth)acryloyl of a polysaccharide, and   wherein the shell comprises ii) a free radical addition product of the multifunctional (meth)acrylate cross-linked with a hydrophobically modified polysaccharide selected from the group consisting of starch alkenyl succinate, starch dodecenyl succinate, starch oleic succinate, starch nonenyl succinate, and starch crotonic succinate,   wherein the polysaccharide is characterized as having hydroxy groups of which from 0.5 up to 40 mole percent of the hydroxy groups of the polysaccharide are substituted with a hydrophobizing agent containing from 1 to 200 carbons, the hydrophobizing agent having at least one unsaturated bond, and   wherein the polysaccharide hydroxy groups are modified with an alkoxylated fatty alcohol comprising the group selected from one or more of an ethoxylated fatty alcohol, a propoxylated fatty alcohol, an ethoxy/propoxy mixture of fatty alcohol adducts, and ethylene oxide-propylene oxide di- or tri-block copolymer.   
     
     
         2 . The microcapsule according to  claim 1  wherein the hydrophobizing agent contains greater than one unsaturated bond or unsaturated fatty acid chains. 
     
     
         3 . The microcapsule according to  claim 1  wherein the polysaccharide is modified with a hydrophobizing agent comprising acryloyl or methacryloyl groups, the acryloyl or methacryloyl groups undergoing an esterification reaction with the hydroxy groups. 
     
     
         4 . The microcapsule according to  claim 1  wherein the polysaccharide is further hydrophobically-modified by admixture with one or more alkylene oxide. 
     
     
         5 . The microcapsule according to  claim 1  wherein the polysaccharide is further cationically-modified. 
     
     
         6 . The microcapsule according to  claim 1  wherein the polysaccharide is further anionically-modified by admixture with chloroacetic acid or through oxidation of the polysaccharide. 
     
     
         7 . A microcapsule comprising a core material and a shell encapsulating the core material, wherein the shell comprises i) a multifunctional (meth)acrylate having a vinyl group cross-linked with a hydroxyl group, carbon, or (meth)acryloyl of a polysaccharide, and the shell comprises ii) a free radical addition product of a multifunctional (meth)acrylate cross-linked with a hydrophobically modified polysaccharide wherein the polysaccharide is characterized as having hydroxy groups of which from 0.5 up to 40 mole percent of the hydroxy groups of the polysaccharide are substituted with a hydrophobizing agent containing from 1 to 200 carbons, wherein the shell comprises a free radical addition product of a multifunctional (meth)acrylate cross-linked with a hydrophobically modified polysaccharide according to Formula I 
       
         
           
           
               
               
           
         
         wherein n 1  is an integer from 1 to 1,000, wherein x is a terminal hydrogen or repeating glucose unit of Formula I from 1 to 50 units, and wherein each A are independently a terminal hydrogen, or an adduct selected from the group consisting of Formula III, Formula V, and Formula VI, 
       
       
         
           
           
               
               
           
         
         wherein each R 2  are independently an alkyl, alkenyl, alkoxy, from 1 to 20 carbons or hydroxy, each R 4  is an alkyl or alkenyl, from 1 to 20 carbons, R 5  is a terminal hydrogen, alkyl, alkenyl, from 1 to 20 carbons, or polyoxyethylene, from 1 to 40 carbons, R 6  is a terminal hydrogen, a hydroxy, an alkoxy, alkyl, alkenyl, alkanol or alkylamine, from 1 to 20 carbons, and R 7  is a terminal hydrogen, (meth)acrylate, alkyl, alkenyl, alkynyl, amine, amide, arenyl, carboxylate, disulfide, ester, ether, epoxide, isocyanate, or sulfide, from 1 to 20 carbons, and n 2  is an integer from 1 to 1,000. 
       
     
     
         8 . The microcapsule according to  claim 1  wherein the shell comprises a random copolymer of the multifunctional (meth)acrylate cross-linked with the polysaccharide, the ratio of polysaccharide to multifunctional (meth)acrylate in the copolymer comprising a ratio of from 1:100 to 10:1 on the basis of weight. 
     
     
         9 . The microcapsule according to  claim 7  wherein the shell comprises a random copolymer of the multifunctional (meth)acrylate cross-linked with the polysaccharide, and on an anhydroglucose unit “AGU” basis the ratio of moles of acrylate per AGU of starch is at most 1500 moles acrylate per AGU of starch. 
     
     
         10 . The microcapsule according to  claim 1  wherein the multifunctional (meth)acrylate comprises a monomer, oligomer or prepolymer having a greater than one ester group on average in the monomer, oligomer or prepolymer, and is selected from ethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, ethylidene dimethacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, pentaerythritol tetraacrylate, tricyclodecane dimethanol dimethacrylate, 1,10 decanediol dimethacrylate, 1,6 hexanediol dimethacrylate, 1,9 nonanediol dimethacrylate, neopentyl glycol dimethacrylate, di-trimethylolpropane tetraacrylate, dipentaerythritol pentaacrylate, ethoxylated (2) bisphenol A dimethacrylate, 2,2 bis[4(methacyloyl ethoxy)phenyl]propane, ethoxylated (3) bisphenol A diacrylate, dipropylene glycol diacrylate, ethoxylated (4) bisphenol A diacrylate, ethoxylated (4) bisphenol A dimethacrylate, 2,2 bis[4-(methacyloyl ethoxy)phenyl]propane, polyethylene glycol trimethylolpropane tri(meth)acrylate, polyester acrylate urethane acrylate and pentaerythritol triacrylate. 
     
     
         11 . The microcapsule according to  claim 1  wherein the microcapsule has a ratio of core to shell up to 99:1 or even 99.5:1, on the basis of weight. 
     
     
         12 . The microcapsule according to  claim 1  wherein the core material comprises a benefit agent. 
     
     
         13 . The microcapsule according to  claim 12  wherein the benefit agent can be selected from the group consisting of perfume, fragrance, agricultural active, phase change material, essential oil, lubricant, colorant, preservative, antimicrobial active, antifungal active, herbicide, antiviral active, antiseptic active, antioxidant, biological active, deodorant, antiperspirant active, emollient, humectant, exfoliant, ultraviolet absorbing agent, corrosion inhibitor, silicone oil, wax, bleach particle, fabric conditioner, malodor reducing agent, dye, optical brightener and mixtures thereof. 
     
     
         14 . An article of manufacture incorporating the microcapsule according to  claim 1 . 
     
     
         15 . The article of manufacture according to  claim 14  wherein the article is selected from the group consisting of a soap, a surface cleaner, a laundry detergent, a fabric softener, a shampoo, a textile, a paper towel, an adhesive, a wipe, a diaper, a feminine hygiene product, a facial tissue, a pharmaceutical, a napkin, a deodorant, a heat sink, a foam, a pillow, a mattress, bedding, a cushion, a cosmetic, a medical device, packaging, an agricultural product, a cooling fluid, a wallboard, and an insulation.